1. Field of the Invention
This invention relates to a dental lamp apparatus used for curing light activated restorative dental materials and for bleaching to whiten teeth. This lamp apparatus provides visible light with a sufficient power density to either rapidly cure restorative material or rapidly bleach a tooth. The lamp apparatus may be switched between these two modes of operation as desired by the dentist. Each mode has a plurality of power levels, one being a ramp power level, particularly suited for curing, enabling the dentist to select a light power density which changes in a controlled fashion best suited for the type of restorative material being cured.
2. Background Discussion
In the current practice of dentistry, it is common to bond porcelain or acrylic laminates to teeth for restorative and cosmetic purposes. The popularity of this procedure is due to its ease, aesthetic appeal, and minimization of trauma to the patient. It is also common to use composite resins or white cosmetic fillings for restorative procedures.
The bleaching to whiten teeth is also a subject of much current interest in the dental community. Besides the pleasurable effects of white teeth, discoloration of non-vital teeth is often a consequence of endodontic treatment, or in traumatized teeth which have experienced a loss of pulpal vitality. Vital teeth may become stained due to tetracycline prescribed for the patient for various medical reasons. Other causes of stained teeth may be drinking water with a high mineral content. Coffee drinking and using tobacco products are also sources of stained teeth. This type of stain is not always removable by conventional prophylactic treatment.
Lamps and lasers have been used for both curing and bleaching. Lamps with a constant beam but low light power density take a relatively long time to cure restorative material, typically, in excess of about 40 seconds. Recently, flash lamps with a high power density have been proposed, but they are deficient because in curing restorative dental materials they are unable to deliver low power levels to produce a ramp profile or pattern which shall be discussed subsequently in greater detail. Such flash lamps must simulate a lower power using a pulse mode which may not have the same effect on the restorative dental materials. Moreover, such flash lamps present a hazard to the eye. Lasers, which are expensive, are deficient because they provide light essentially only at one wavelength. This is undesirable, because the light activated materials react most effectively with light over a selected wavelength band, usually from about 400 to 600 nanometers (nm). Moreover, the lasers cannot normally be used for both curing and bleaching. Because of the high light power density from the lasers, the time it takes to cure restorative material is relative short, usually less than about 10 seconds. But great care must be employed when using lasers because this high power density of light can cause severe injury if the beam of laser light accidentally, for example, strikes the eye even briefly.
Unlike the instant invention, high powered visual light sources (VLS) may use a mercury xenon plasma arc lamp. There are other light sources, such as flashes or strobes, that may be employed. Additionally, such a high-powered instrument can use a high voltage spike to initiate the arc and an expensive power supply. These arc lamps are hard to use as they are quite inefficient and expensive to operate. The bulbs and power supply are expensive. Some bulbs require a 15 minute warm-up period. Adding to the expense and inconvenience of these bulbs is their short life expectancy and deteriorating output.
An example of curing lamps used to cure certain composite materials applied is taught in U.S. Pat. No. 4,666,406 by Kanca, III. This device uses a fiber optic wand with a light transmitting fiber optic tip. This art is concerned with using solid fibers to transmit light to cure dental composite material. There is no mention of use of this device to facilitate tooth bleaching.
Optical fibers are again mentioned in, for example, U.S. Pat. No. 4,608,622 to Gosner. This art is again dealing with fiber light conducting bundles to transmit light to cure dental resin material as well as for oral illumination. Again, there is no mention of bleaching.
Curing lights with other ancillary features include U.S. Pat. No. 5,125,842 to Hiltunen. In this patent, monitoring the depth of cure is key, as is curing dental restorations.
U.S. Pat. No. 4,747,662 to Fitz discusses fiber optics with a liquid core and a fluoroplastic cladding. Fitz does not mention the light with relation to dental procedures.
Nath, in U.S. Pat. No. 3,995,934 also mentions a flexible light guide with a liquid center but does not mention dental use. Nath does mention the polymerization of dental resins in U.S. Pat. No. 4,009,382 in which a flexible light guide is described. There is, however, no mention of the light as a tool for bleaching, or whitening, of teeth.
There have also been various methods and systems available for tooth bleaching. Much of this technology, as evidenced by U.S. Pat. No. 5,645,428 to Yarborough, show that laser technology plays a large part in bleaching, or tooth whitening. Yarborough uses laser light to activate bleaching agents to accomplish tooth whitening. More specifically, an oxygen radical is activated by laser light.
A non-laser method for bleaching stained teeth by applying a concentrated solution of peroxide to stained teeth and focusing a beam of light at the teeth has been patented by Friedman in U.S. Pat. No. 4,661,070. The focused beam contains the combination of ultraviolet and infrared energy for activating the peroxide solution.
Another composition for bleaching teeth comprises aqueous hydrogen peroxide and a non-aqueous component which are combined to treat the teeth in response to the application of optical energy as disclosed by Cornell in U.S. Pat. No. 5,032,178. This patent teaches the use of chemical compositions, such as manganese sulfate and ferrous sulfate, to activate catalytically the bleaching activity of the light-activated hydrogen peroxide composition. The process of the instant invention uses no such materials.
The use of bleaching, as with peroxide, to whiten teeth appears less often in dental literature than laser whitening for use by dentists. Options such as at-home bleaching kits and whitening toothpastes are limited in their abilities and not comparable to laser bleaching or the professional dental bleaching results of this invention.